The European Union escalated its trans-Atlantic fight with Microsoft on Thursday, threatening new multimillion fines against the software maker over claims it fails to offer rivals a fair deal on licenses for helping servers work with Windows. In response, Microsoft charged that the treatment it receives from the EU is unmatched around the world and harmed Europe's efforts to become a thriving high-tech economy. The EU said Microsoft could face fines as high as euro3 million (US$4 million) a day, accusing the software company of trying to protect its interests by overcharging rivals for complete and accurate interface documentation - which would allow them to interoperate with Windows PCs and servers - on reasonable and non-discriminatory terms.